• Korean Journal of Materials Research
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• v.10 no.4
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• pp.270-275
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• 2000

The Pt/YMnO$_3$/Y$_2$O$_3$/Si structure for metal/ferroelectric/insulator/semiconductor(MFIS)-FET was fabricated and effect of $Y_2$O$_3$layer on the properties of MFIS structure was investigated. The $Y_2$O$_3$ thin films on p-type Si(111) substrate deposited by Pulsed Laser Deposition were crystallized along (111) orientation irrespective of the deposition temperatures. Ferroelectric YMnO$_3$ thin films deposited directly on p-type Si (111) by MOCVD resulted in Mn deficient layer between Si and YMnO$_3$. However, YMnO$_3$ thin films having good quality and stoichiometric composition can be obtained by adopting $Y_2$O$_3$ buffer layer. The memory window of the $Y_2$O$_3$thin films with YMnO$_3$ film is greater than that of the YMnO$_3$ thin films without $Y_2$O$_3$ film after the annealing at 85$0^{\circ}C$ in vacuum ambient(100mtorr). The memory window is 1.3V at an applied voltage of 5V.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.4
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• pp.251-258
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• 2004

Soil testing for silicon (Si) in the upland soils has not been sufficiently investigated. The objective of this study was to identify a suitable Si extraction method for upland soils of oriental melon (Cucumis melo L.). Thirty-eight surface soil samples and matured leaf samples were collected from plastic film houses in Sungju, Gyeongbuk province. In the laboratory, six different methods were used for extracting Si from the soils. The methods included 0.5 N HCl extraction, 1 N sodium acetate buffer (PH 4.0) extraction, citric acid 1% extraction, water extraction, Tiis buffer pH 7.0 extraction, and extraction after incubation with water for 1 week. The concentration of dissolved Si in soil extracts from all methods was determined colorimetrically. With 1 N sodium acetate buffer extraction, as the available soil Si increased, the concentration ofSi in oriental melon leaf increased until around $14g\;SiO_2\;kg^{-1}$ was reached in the form of a saturation curve. Also, among the methods studied, extraction with 1 N sodium acetate buffer was the only method provided a significant linear correlation with oriental melon leaf Si content in the range of extractable soil Si lower than the level which inducing Si saturation in oriental melon leaf. These results indicate that 1 N sodium acetate buffer extraction procedure is the best soil Si test method for upland soils of oriental melon. This sodium acetate buffer extraction procedure is rapid and quite well acquainted with scientists and farmers, since the method has been used for routine paddy soil testing.

• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.139.1-139.1
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• 2007

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.7
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• pp.293-297
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• 2003

Silicon dioxide (SiO$_2$) layers were fabricated on Si$_3$N$_4$/SiO$_2$/Si layer structures by low pressure chemical vapor deposition (LPCVD). Potassium and aluminum were then coimplanted by implanting potassium ions with the energy of 100 ［keY］ and dose of 5x10$^{16}$ [cm￣$^2$］ and 1x10$^{17}$ [cm￣$^2$］ into an aluminum buffer layer on the SiO$_2$Si$_3$N4/SiO$_2$/Si structure. The pH, pNa, and pK ion sensitivities of the resulting layers were investigated and compared to those of as-deposited silicon dioxide layer. The pK-sensitivity of the silicon dioxide was enhanced by the K and Al coimplantation. On the contrary, the pH and pNa-sensitivities of the coimplanted silicon dioxides were quite lower than that of the as-deposited silicon dioxide.

• Journal of the Korean Magnetics Society
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• v.25 no.2
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• pp.43-46
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• 2015

$Si(100){\backslash}200nm$ $SiO_2{\backslash}5nm$ $Ta{\backslash}5nm$ $MgO{\backslash}35nm$ $Fe_3O_4$ multi-layers were prepared by using RF-sputtering and ultra-high vacuum molecular beam epitaxy (UHV-MBE) techniques. After post-annealing the multi-layers at $500^{\circ}C$ for 1 hour under the high vacuum of ${\sim}1{\times}10^{-6}Torr$, we observed ferromagnetic properties at room temperature as well as the Verwey transition which is the typical features of magnetite crystals formed. We have carried out a comparative study of the effect of Ta buffered layer on the crystallinity and magnetic properties of $Fe_3O_4$ thin films prepared under different growth and annealing conditions.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.326-328
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• 1995

SiC buffer layers were grown on Si(100) substrates by ultra-high-vacuum electron cryclotron resonance plasma (UHV ECR plasma) from $CH_4/H_2$ mixture at 700$^{\circ}C$. The electron densities and temperature were measured by single probe. The axial plasma potentials measured by emissive probe had the double layer structure at positive substrate bias. Piranha cleaning was carried out as ex-situ wet cleaning. Clean and smooth silicon surface were prepared by in-situ hydrogen plasma cleaning at 540$^{\circ}C$. A short exposure to hydrogen plasma transforms the Si surface from 1$\times$1 to 2$\times$1 reconstruction. It was monitored by reflection high energy electron diffraction (RHEED). The defect densities were analysed by the dilute Schimmel etching. The results showed that the substrate bias is important factor in hydrogen plasma cleaning. The low base pressure ($5\times10^{-10}$ torr) restrains the $SiO_2$ growth on silicon surface. The grown layers showed different characteristics at various substrate bias. RHEED and K-ray Photoelectron spectroscopy study showed that grown layer was SiC.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.319-320
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• 2009

In this study, high-quality Al-N doped p-type ZnO thin films were deposited on n-type Si (100) wafer or Si coated with buffer layer by DC magnetron sputtering in the mixture of $N_2$ and $O_2$ gas. The target was ceramic ZnO mixed with $Al_2O_3$ (2 wt%). The p-type ZnO thin film showed higher carrier concentration $2.93\times10^{17}cm^{-3}$, lower resistivity of $5.349\;{\Omega}cm$ and mobility of $3.99\;cm^2V^{-1}S^{-1}$, respectively. According to PL spectrum, the Al donor energy level depth ($E_d$) of Al-N codoped p-type ZnO film was reduced to about 51 meV, and the N acceptor energy level depth ($E_a$) was reduced to 63 meV, respectively.

• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.243.1-243.1
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• 2007

• Journal of the Korean Ceramic Society
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• v.37 no.11
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• pp.1105-1113
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• 2000

Bioglass 조성 중 45S5 (46.1SiO$_2$.24.4$Na_2$O.26.9CaO.2.6P$_2$O$_{5}$ : 몰비)를 기본 조성으로 하여 46P4 (46.2SiO$_2$.49.5CaO.4.3P$_2$O$_{5}$ : 몰비), 46SF (46.1SiO$_2$24.4$Na_2$O.16.1CaO.2.6P$_2$O$_{5}$.10.8CaF : 몰비) 그리고 55SF (55.1SiO$_2$.9.2$Na_2$O.27.8CaO.3.4P$_2$O$_{5}$.4.5CaF : 몰비)를 제조하여 tris-완충용액 및 유사 생체용액(simulated body fluid)에서 반응시킨 후 생체활성유리의 표면에 생성되는 아파타이트 결정형에 관하여 연구하였다. 45S5 유리를 tris-완충용액에 반응시켰을 경우 6시간 반응시부터 수산화 아파타이트가 생성되었으나 유사 생체용액에 반응시켰을 경우에는 24시간까지도 수산화 아파타이트 결정이 생성되지 못하고 비정질 상태의 칼슘 인산염만 형성되었다. tris-완충용액에 각 조성의 유리를 200시간 반응시킨 경우 불소를 함유하지 않은 유리에서는 잎사귀 모양의 수산화 아파타이트가, 불소를 함유한 유리에서는 구상의 플루오르 아파타이트가 형성되었다. 그러나 유사 생체용액에 각 조성의 유리를 200시간 반응시켰을 경우 불소를 함유하지 않은 유리에서는 누에고치형의 수산화 아파타이트가 형성되었고 불소를 함유한 유리에서는 무정형의 칼슘 인산염이 생성되었다.

• Journal of the Korean Magnetics Society
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• v.12 no.2
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• pp.41-45
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• 2002

The low-field tunnel-type magnetoresistance (MR) properties of sol-gel derived $La_{0.7}Pb_{0.3}MnO_3(LPMO)$ thin film deposited on different substrate have been investigated. Polycrystalline thin films were fabricated by spin-coating on $SiO_2/Si(100)$ substrate and that with yttria-stabilized zirconia (YSZ) buffer layer, while c-axis-oriented thim film was grown on $LaAlO_3(001)$ (LAO) single crystal substrate. The full width half maximum (FWHM) of the rocking curve scan of LPMO/LAO film is $0.32^{\circ}$. Tunnel-type MR ratio is 0.52 % in $LPMO/SiO_2/Si$(100) film and that of $LPMO/YSZ/SiO_2/Si$(100) film is as high as 0.68 %, whereas that of LPMO/LAO(001) film is less than 0.4 % under the applied field of 500 Oe at 300 K. Well-pronounced MR hysteresis was registered with an MR peak in the vicinity of the coercive field. The low-field tunnel-type MR characteristics of thin films deposited on different substrates originates from the behavior of grain boundary properties.